macknigiit



(No Model.)

J. W. MAGKNIGHT.

FIRE PROOF CEILING.

Patented Aug. 1-3, 1889.

May/

FIE]

IINIV/ENIWJR *Wlr M UNITED STATES PATENT OFFICE.

JOHN W. MACKNIGIIT, OF NEIV YORK, N. Y.

FIRE-PROOF CEILING.

SPECIFICATION forming part of Letters Patent No. 408,922, dated August13, 1889. Application filed January 2, 1889. Serial No. 295,198. (Nomodel.)

To all whom it may concern:

Be it known that I, JOHN WV. MAC-KNIGHT, of New York city, New York,have invented an Improved Fire-Proof Ceiling, of which the following isa specification.

This invention relates to an improved fireproof ceiling of greatdurability; and the invention consists in the various features ofimprovement, more fully pointed out in the claims.

111 the accompanying drawings, Figure l is a perspective view of myimproved fireproof ceiling, showing it in the process of formation. Fig.2 is avertical transverse section through the completed ceiling, butwith the platform still in place.

The letters a a represent a series of parallel I-beams, from which Isuspend temporarily a platform Z) by hangers 0. Upon this platformbetween the beams I sift a thin layer of gravel or broken stone 07..Next, I place across the spaces between the beams a series of joists (Z,which rest upon the lower flanges of the beams. These joists should beplaced at about an angle of fortyfive degrees to the beams, as shown,and the joists to the right and left of any one beam should break line,Fig. 1. Between the joists there is'now packed flush with the surfacethereof a concrete mixture c, composed, preferably, of three parts ofashes, three parts of gravel, one part of cement, and enough water togive to the mass the consistency of brown sugar. hile this mass is stillmoist, the joists (Z are removed and the grooves thus formed are filledin with a mixture f, composed of about three parts of crushed stone(preferably crushed trap-rock) and one part of cement, to which a littleammonia, iron, and alum may be added. This mixture will thus be formedinto strips that rest upon the lower flanges of beams 04. The masses 6 fwill set together, and will adhere in the act of setting to form oneunited mass. Owing to the oblique positionof the joists (Z, the strips fwill assume a similar inclination, thus assuring increased strength. Thestrips f are, as will be seen, formed of much stronger material than theconcrete in which they are embedded. As they unite with the concrete insetting, they will strengthen the whole structure and prevent it fromwarping and cracking. The space above the masses 6 f should be filled inwith a layer of dry'ashes or similar material 9 flush with the upperedge of beams a. The ceiling being completed, the platform I) isremoved, and the usual finish is applied to the layer n of gravel.

WVhat I claim is- 1. The combination of beams a, with a series of stripsf of crushed stone and cement between the beams, and with concrete 6,inelosing strips f at the sides, substantially as specified.

'2. The combination of I-beams a, with the oblique strips f of crushedstone and cement resting upon the lower flanges of the I-beams, and withthe concrete 8 at the sides of strips and with a superposed layer g ofashes and a bottom layer or of gravel, substantially as specified.

' JOHN IV. MACKNIGHT. Witnesses: F. v. BRIEsEN,

HENRY E. ROEDER.

